Solid-state imaging device and method for producing the same

ABSTRACT

In the solid-state imaging device of the present invention having a photoelectric conversion section and a charge transfer section equipped with a charge transfer electrode for transferring an electric charge generated in the photoelectric conversion section, the charge transfer electrode has an alternate arrangement of a first layer electrode comprising a first layer electrically conducting film and a second layer electrode comprising a second layer electrically conducting film, which are formed on a gate oxide film comprising a laminate film consisting of a silicon oxide film and a metal oxide thin film, and the first layer electrode and the second layer electrode are separated by insulation with an interelectrode insulating film comprising a sidewall insulating film formed by a CVD process to cover the lateral wall of the first layer electrode.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to a solid-state imaging device and aproduction method thereof, more specifically, the present inventionrelates to the formation of an interelectrode insulating film of asolid-state imaging device.

2. Background Art

The solid-state imaging device utilizing CCD (Charge-Coupled Device)used for an area sensor and the like has a photoelectric conversionsection comprising a photodiode or the like and a charge transfersection equipped with a charge transfer electrode for transferring asignal charge from the photoelectric conversion section. As for thecharge transfer electrode, plural charge transfer electrodes areadjacently disposed on a charge transfer path formed on a semiconductorsubstrate and sequentially driven.

With recent development of CCD having a large number of pixels, demandsfor high resolution and high sensitivity of a solid-state imaging deviceare more and more increasing, and the number of imaging pixels has beenincreased to giga-pixels or more.

Under these circumstances, since reduction of the light-receiving areamust be avoided to ensure high sensitivity, it is obliged to reduce theoccupation area of the charge transfer electrode.

Incidentally, the interelectrode insulating film provided between chargetransfer electrodes can be thinly formed by the oxidation (900 to 950°C.) of an electrode material. However, in order to form a thin andgood-quality oxide film, the oxidation temperature needs to be high of900° C. or more as described above and impurity diffusion on thesubstrate side proceeds due to heat history by oxidation, incurringvarious problems such as deterioration of transfer efficiency andreduction of sensitivity.

In this way, the formation of an interelectrode insulating film by usingthermal oxidation is a big obstacle standing in the way of developing afine (high-quality) solid-state imaging device with a large number ofpixels.

As described in JP-A-2003-197896 (the term “JP-A” as used herein meansan “unexamined published Japanese patent application”), a chargetransfer electrode having a multilayer structure where theinterelectrode insulting film is formed by a CVD (Chemical VaporDeposition) process has been proposed with an attempt to reduce thetemperature at the formation of the interelectrode insulating film.

In the case of a charge transfer electrode having a single-layerelectrode structure, when the formation of an interelectrode gap and theembedding of an insulating film therein are performed by a one-timephotolithography process, a fine pattern exceeding the resolution limitcan be hardly formed and moreover, the embedding of an insulting film inthe interelectrode gap having a high aspect ratio is extremelydifficult. By taking account of such situation, there has been proposeda structure where a sidewall is formed as an interelectrode insulatingfilm on the lateral wall of a first layer electrode formed alternatelyand a second layer electrode is formed through the sidewall (refer toJP-A-5-129583) In such circumstances, for the purpose of highintegration, the present inventors have proposed a solid-state imagingdevice where a sidewall comprising a silicon oxide film formed by alow-temperature CVD process is used for one lateral wall of adjacentcharge transfer electrodes (refer to Japanese Patent Application No.2004-281721).

Such a sidewall structure is an excellent structure requiring nophotolithography process and being self-alignedly formable byanisotropic etching. In many cases, the gate oxide film has beenconventionally constituted by a three-layer structure comprising a 25nm-thick silicon oxide film (bottom oxide film), a 50 nm-thick siliconnitride film, and a 10 nm-thick silicon oxide film (top oxide film). Atthe anisotropic etching, the silicon nitride film of the three-layerstructure gate oxide film works as a stopper, and the film loss of thegate oxide film is allowed to occur only in the top oxide film.Accordingly, the anisotropic etching enables efficient formation of acharge transfer electrode with high reliability.

In this way, in the production of a solid-state imaging device, it isdemanded to avoid a process at a temperature as high as incurringextension of the diffusion length of an already doped impurity, forensuring a finer fabrication tolerance, prevent deterioration of thecharge transfer efficiency, and realize high-speed driving andhigh-quality image output. To cope with these requirements, a CVDprocess, particularly, a CVD process performed at a low temperature of700 to 850° C., has been introduced.

On the other hand, the structure using an ONO film for the gate oxidefilm has a problem that an electric charge is readily trapped into thesilicon nitride film to cause voltage shift due to depletionparticularly in the read-out section to which a high voltage is applied,and a malfunction may occur.

From this reason, the fine fabrication of a solid-state imaging deviceis associated with a demand for a structure not containing siliconnitride in the gate oxide film, further a structure equipped with a thingate oxide film having high withstand voltage.

SUMMARY OF THE INVENTION

An object of the invention is to provide a solid-state imaging devicefree from characteristic deterioration by preventing charge trappinginto the gate oxide film and assured of high reliability by using ahigh-quality interelectrode insulating film which is easilymicrofabricated.

(1) A solid-state imaging device comprising: a semiconductor substrate;a photoelectric conversion section; a gate oxide film comprising atwo-layer film containing a silicon oxide film and a metal oxide thinfilm; a charge transfer section comprising a charge transfer electrodefor transferring an electric charge generated in the photoelectricconversion section, the charge transfer electrode comprising: a firstelectrode comprising a first conductive film; and a second electrodecomprising a second conductive film, the first electrode and the secondelectrode being disposed on a surface of the semiconductor substratethrough the gate oxide film and alternatively arranged; and aninterelectrode insulating film comprising a sidewall insulating filmcovering the lateral wall of the first electrode, the interelectrodeinsulating film separating and insulating the first electrode from thesecond electrode.

According to this constitution, the gate oxide film is composed of atwo-layer film consisting of a silicon oxide film and a metal oxide thinfilm, so that the withstand voltage can be elevated and a highlyreliable solid-state imaging device can be provided. Furthermore, sincea highly reliable structure can be formed even when the gate oxide filmdoes not contain a silicon nitride film, the gate oxide film can becomposed of a silicon oxide film and charge trapping thereinto can beprevented.

(2) The solid-state imaging device as described in the item (1), whereinthe metal oxide thin film has high dielectric constant.

According to this constitution, the metal oxide thin film is composed ofa high dielectric thin film such as aluminum oxide, so that satisfactoryetching selectivity can be ensured at the anisotropic etching of thesilicon oxide film for forming a sidewall insulating film and a highlyreliable electrode structure can be formed without causing film loss ofthe gate oxide film. Furthermore, even in the case where the metal oxidethin film is caused to remain as it is, this constitutes a part of thegate oxide film below the second layer electrode, so that a thin chargetransfer electrode structure with high withstand voltage can beobtained. Here, the metal oxide thin film acts as an etching stopperlayer at the etching of silicon oxide.

(3) The solid-state imaging device as described in the item (2), whereinthe metal oxide thin film comprises at least one element selected fromthe group consisting of Al, Ti, Hf, Zr, La and Y.

According to this constitution, even when the metal oxide thin film iscaused to remain as the gate oxide film of the second layer electrode, adense and highly reliable gate oxide film can be obtained. Also, thegate oxide film below the first layer electrode and the gate oxide filmbelow the second layer electrode can have the same composition, and thecharacteristic properties can be uniformized. Furthermore, by virtue ofgood etching selectivity to silicon oxide, a dense interelectrodeinsulating film with high withstand voltage can obtained. In addition,the threshold voltage can be controlled by adjusting the Alconcentration in the Hf oxide, and a structure where the dielectricconstant is increased by decreasing the Al concentration in the read-outregion is also effective.

(4) The solid-state imaging device as described in the item (2), whereinthe metal oxide thin film has low dielectric constant.

According to this constitution, the gate oxide film can have a lowdielectric constant, and a solid-state imaging device capable of drivingat a higher speed can be fabricated.

(5) The solid-state imaging device as described in the item (1), whereinthe silicon oxide film comprises a silicon oxide film formed by achemical vapor deposition method.

(6) The solid-state imaging device as described in the item (1), whereinthe silicon oxide film comprises a HTO film.

According to this constitution, the film quality can be enhanced and ahighly reliable interelectrode insulating film can be formed. The HTOfilm can be formed at a low temperature and has a dense and good filmquality, so that a high-quality sidewall insulating film can be formed.As for the film-forming conditions of the HTO film, the film ispreferably formed at a substrate temperature of 700 to 850° C.

In addition, when the first layer electrically conducting film and thesecond layer electrically conducting film are composed of asilicon-based electrically conducting film, the single-layer fabricationcan be easily attained by CMP or etchback and therefore, the processingis facilitated.

In the case of constructing a two-layer electrode structure, when thefirst layer electrically conducting film and the second layerelectrically conducting film are composed of a polymetal, flattening ispossible and the resistance is low, so that both thickness reduction andhigh-speed driving can be realized and in turn, a high-sensitivityhighly reliable solid-state imaging device capable of microfabricationcan be obtained.

This constitution is effective particularly in the fabrication of asolid-state imaging device having a microfine structure where theinterelectrode distance between the first and second electrodes, thatis, the thickness of the interelectrode insulating film, is 0.1 μm orless.

When the interelectrode distance is 0.1 μm or less, pattern formation isdifficult, but according to this method, the pattern can be easilyformed by a lateral wall leaving technique utilizing CVD or anisotropicetching of an oxide film. Furthermore, by virtue of the two-layerstructure, withstand voltage can be ensured despite small film thicknessand a fine pattern can be easily formed.

(7) A method for producing a solid-state imaging device, the solid-stateimaging device containing: a photoelectric conversion section; and acharge transfer section having a charge transfer electrode fortransferring an electric charge generated in the photoelectricconversion section, comprising: sequentially laminating a silicon oxidefilm and a metal oxide thin film on a semiconductor substrate; forming afirst electrode comprising a first conductive film; forming a siliconoxide film on the top of the first electrode; anisotropically etchingthe silicon oxide film by using the metal oxide thin film as an etchingstopper to form a sidewall insulating film on the lateral wall of thefirst electrode; and forming a second electrode comprising a secondconductive film through the sidewall insulating film so as to beinsulated and separated from the first electrode.

According to this constitution, the top side of the gate oxide film iscomposed of a metal oxide thin film and by using this as an etchingstopper, a sidewall can be successfully formed, so that unlike siliconnitride, charge trapping can be prevented and a compact and highlyreliable solid-state imaging device can be fabricated.

(8) The method for producing a solid-state imaging device as describedin the item (7), which comprises: removing the metal oxide thin film onthe gate oxide film after the forming of the sidewall insulating film,the first insulating film being exposed from the sidewall insulatingfilm.

According to this constitution, if desired, the gate oxide film in thesecond layer electrode forming region may be constructed not to containa metal oxide thin film.

(9) The method for producing a solid-state imaging device as describedin the item (8), wherein the second electrode is formed by removing andflattening the second conductive film on the first electrode to separatethe second conductive film so that the second electrode can be formedbetween the first electrodes.

According to this constitution, a single-layer electrode structure canbe efficiently obtained.

In method for producing a solid-state imaging device of the presentinvention, the step of forming a sidewall insulating film comprises astep of forming an HTO film by a CVD process.

According to this constitution, a highly reliable solid-state imagingdevice can be obtained without passing through a high-temperatureprocess.

(10) The method for producing a solid-state imaging device as describedin the item (8), wherein the forming of the first electrode comprises:forming the first conductive film; forming a hard mask comprising aninsulting film on the first conductive film; and

selectively removing the first conductive film by using the hard mask.

According to this method, a first layer electrode pattern with highprecision and high reliability can be formed. Also, this hardmask actsas a removal-suppressing layer (stopper layer) of suppressing theremoval of the first layer electrode at the time of flattening thesecond layer electrically conducting film, so that a flat surface can beefficiently formed without bringing about film loss.

The present invention includes the above-described method for producinga solid-state imaging device, wherein the hardmask is a single-layerfilm comprising a silicon oxide film, and the second layer electricallyconducting film is laminated on the hardmask.

(11) The method for producing a solid-state imaging device as describedin the item (10), wherein the hard mask comprises a two-layer filmcontaining the silicon oxide film and a silicon nitride film, and thefirst insulating film is laminated on the hard mask.

According to this method, the first layer electrically conducting filmconstituting the first layer electrode can be prevented fromcontamination at the resist ashing. Furthermore, the hardmasksuccessfully acts as a removal-suppressing layer for the first layerelectrode in the patterning process of the second layer electricallyconducting film and also successfully acts as a removal-suppressinglayer on the first layer electrode at the time of forming a sidewallinsulating film by anisotropic etching after the patterning of the firstlayer electrically conducting film.

In the case of forming a single-layer electrode structure by performingflattening with use of chemical mechanical polishing (CMP) or a resistetchback process after the second layer electrically conducting film isformed, the hard mask successfully acts as a removal-suppressing layerfor the first layer electrode.

According to the present invention, the gate oxide film is composed of atwo-layer film consisting of a silicon oxide film and a metal oxide thinfilm, so that even when the gate oxide film does not contain a siliconnitride film, high withstand voltage can be obtained. Furthermore, themetal oxide thin film acts as an etching stopper layer at the formationof a sidewall insulting film, so that a highly reliable solid-stateimaging device assured of easy production can be provided.

BRIEF DESCRIPTION OF THE DRAWINGS

The invention disclosed herein will be understood better with referenceto the following drawings of which:

FIG. 1 is a cross-sectional view that illustrates the solid-stateimaging device in Embodiment 1 of the present invention;

FIG. 2 is a top view that illustrates the solid-state imaging device inEmbodiment 1 of the present invention;

FIG. 3 is a view that illustrates the production process of thesolid-state imaging device in Embodiment 1 of the present invention;

FIG. 4 is a view that illustrates the production process of thesolid-state imaging device in Embodiment 1 of the present invention; and

FIG. 5 is a view that illustrates the production process of thesolid-state imaging device in Embodiment 1 of the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Exemplary embodiments of the present invention are described below byreferring to the drawings.

Embodiment 1

This solid-state imaging device is characterized in that, as illustratedin FIGS. 1 and 2, the gate oxide film 2 comprises a two-layer filmconsisting of a silicon oxide film 2 a and a hafnium oxide layer 2S.This hafnium oxide layer 2S has a role of acting as an etching stopperlayer in the anisotropic etching process at the formation of a sidewallinsulating film and at the same time, preventing charge trapping.Although the solid-state imaging device has the structure of a normalsolid-state imaging device except for this, a first layer electrode 3 acomprising a polycrystalline silicon layer as the first layerelectrically conducting film and a second layer electrode 3 b comprisinga polycrystalline silicon layer as the second layer electricallyconducting film are alternately juxtaposed on the gate oxide film 2, andthe interelectrode insulating film is composed of a sidewall insulatingfilm 5 comprising an HTO film (silicon oxide film) formed by a CVDprocess. The numeral 6 is a silicon oxide film. FIG. 1 is across-sectional view, and FIG. 2 is a plan view. FIG. 1 is an A-Across-sectional view of FIG. 2.

According to this constitution, the gate oxide film is composed of atwo-layer film consisting of a silicon oxide film 2 a and a hafniumoxide film 2S, so that even at the formation of a sidewall insulatingfilm comprising an HTO film, a high-quality sidewall insulating filmwith high withstand voltage can be formed at a low temperature withoutcausing film loss of the gate oxide film and the extension of thediffusion length can be prevented. Furthermore, according to thisconstitution, a first layer electrode 3 a and a second layer electrode 3b are alternately juxtaposed, so that a single-layer electrode structurehaving a flat surface can be easily formed.

Other structures are the same as those of the conventional solid-stateimaging device. That is, the solid-state imaging device is characterizedby: comprising a photoelectric conversion section 30 and a chargetransfer section 40 equipped with a charge transfer electrode fortransferring an electric charge generated in the photoelectricconversion section 30; comprising an intermediate layer 70 including,for example, a light-shielding film (not illustrated) formed to have anopening in the photoelectric conversion section and a flattening filmcomprising a BPSG (borophosphosilicate glass) film filled in thephotoelectric conversion section to give a nearly flat surface; andfurther forming a filter 50 and a lens 60 on the intermediate layer.

By virtue of such a constitution, an interelectrode insulating film canbe easily formed without deterioration of the gate oxide film, and goodflattening of the surface and great reduction in the thickness can beattained.

On the silicon substrate 1, a plurality of photodiode regions 30 areformed, and a charge transfer section 40 for transferring a signalcharge detected in the photodiode region 30 is formed between photodioderegions 30.

The charge transfer channel allowing for travelling of the signal chargetransferred by the charge transfer electrode is not illustrated in FIG.2 but is formed in the direction intersecting with the direction towhich the charge transfer section 40 is extending.

As for the interelectrode insulating film, those formed in the vicinityof the boundary between the photodiode region 30 and the charge transfersection 40 are omitted in FIG. 2.

As illustrated in FIG. 1, in the silicon substrate 1, a photodiode 30, acharge transfer channel 33, a channel stop region 32 and a chargeread-out region 34 are formed, and on the surface of the siliconsubstrate 1, a gate oxide film 2 is formed. On the surface of the gateoxide film 2, charge transfer electrodes (a first layer electrodecomprising a first layer electrically conducting film 3 a and a secondlayer electrode comprising a second layer electrically conducting film 3b) are formed and juxtaposed with intervention of an interelectrodeinsulating film 5 comprising a sidewall insulating film formed on thelateral wall of the first layer electrode, whereby a single-layerelectrode structure is constructed.

The charge transfer section 40 is as described above, but as illustratedin FIG. 1, an intermediate layer 70 is formed on the top of the chargetransfer electrode of the charge transfer section 40. More specifically,an antireflection layer 7 comprising a silicon nitride film is formed, alight-shielding film 71 is provided in the portion excluding thephotodiode region 30 (photoelectric conversion section), and aflattening film 72 comprising a BPSG film is formed in the recess part.Furthermore, as upper layers, a passivation film 73 comprising atransparent resin film and a flattening layer 74 under filter areprovided.

On the top of the intermediate layer 70, a color filter 50 (50B, 50G)and a microlens 60 are provided. If desired, a flattening layer 61comprising an insulating transparent resin or the like may be filledbetween the color filter 50 and the microlens 60.

In this Example, a solid-state imaging device having a so-calledhoneycomb structure is described, but the same is of course applicablealso to a square lattice-type solid-state imaging device.

The production process of this solid-state imaging device is describedin detail below by referring to FIGS. 3 and 4.

First, a gate oxide film 2 comprising a silicon oxide film having a filmthickness of 50 nm and a hafnium oxide layer 2S having a film thicknessof 50 nm is formed on the surface of an n-type silicon substrate 1having an impurity concentration of about 1.0×10¹⁶ cm⁻³.

Subsequently, a first layer polycrystalline silicon film as a firstlayer electrically conducting film (3 a) having a film thickness of 50to 300 nm is formed on the gate oxide film 2 by a reduced-pressure CVDprocess. The substrate temperature here is set to 500 to 600° C. On thislayer, an HTO film 4 having a film thickness of 50 to 300 nm issequentially laminated by a CVD process at a substrate temperature of850° C. (from 700 to 850° C.) (FIG. 3(b)).

Thereafter, a resist pattern R1 is formed by photolithography (FIG. 3(c)) and through this pattern as the mask, the HTO film 4 is etched byreactive ion etching using CHF₃, C₂F₆, O₂ and He. Then, the resistpattern is removed by ashing to form a hardmask comprising the HTO film4.

By using the thus-obtained hardmask comprising the HTO film 4, the firstlayer electrically conducting film 3 a is etched (FIG. 4 (a)). At theetching, reactive ion etching using a mixed gas of HBr and O₂ isperformed to form a first layer electrode and wiring of peripheralcircuits. Here, an etching apparatus such as ECR (electron cyclotronresonance) system or ICP (inductively coupled plasma) system ispreferably used.

On this layer, an HTO film 5 having a film thickness of 30 to 200 nm isformed by a reduced-pressure CVD process at a high temperature (FIG.4(b)).

Then, the HTO film 5 accumulated in the horizontal portions is removedby reactive ion etching and allowed to remain on the lateral wall,thereby forming a sidewall (insulating film) (FIG. 4(c)). At this time,the hafnium oxide layer 2S acts as an etching stopper.

Subsequently, a polycrystalline silicon film as the second layerelectrically conducting film 3 b is formed thereon by a reduced-pressureCVD process to a thickness larger than the height of the first layerelectrically conducting film 3 a. At this time, the substratetemperature is set to 500 to 600° C. (FIG. 5(a)).

Furthermore, the second layer electrically conducting film 3 b in theprojected portions is removed by an etchback process to flatten thesurface (FIG. 5(b)). In this way, the charge transfer section is formed.

Thereafter, an HTO film 6 having a film thickness up to 50 nm and asilicon nitride film 7 as an antireflection film are formed by areduced-pressure CVD process (see, FIG. 1).

Subsequently, patterning of the second layer electrode (second layerelectrically conducting film) is performed by photolithography, therebyopening a window in the photoelectric conversion section.

After forming an intermediate layer 70 such as antireflection film,light-shielding layer and flattening layer, a color filter 50, amicrolens 60 and the like are formed to obtain a solid-state imagingdevice illustrated in FIGS. 1 and 2.

According to this solid-state imaging device, the gate oxide film iscomposed of a silicon oxide film 2 a and a hafnium oxide layer 2S, andthe sidewall can be successfully formed by anisotropic etching using thehafnium oxide layer 2S as an etching stopper, so that a compact andhighly reliable solid-state imaging device can be fabricated.Furthermore, the side wall is composed of an HTO film, and alow-resistance single-layer structure electrode is constructed at a lowtemperature, so that a high-precision fine solid-state imaging devicecan be fabricated without extension of diffusion length and high-speeddriving and microfabrication can be realized

According to this method, a fine structure having an interelectrodedistance of about 0.1 μm or less can be formed.

Incidentally, the etching stopper layer used at the anisotropic etchingfor forming the sidewall is the first insulating film 5 a and therefore,film loss due to overpolishing of the gate oxide film can be prevented.

Embodiment 2

In Embodiment 1, a laminate film consisting of a silicon oxide film anda hafnium oxide layer is used as the gate oxide film, but in place ofthe high dielectric thin film such as hafnium oxide layer, a lowdielectric thin film having etching resistance may be used at theetching of silicon oxide.

According to this constitution, a thin and highly reliable gate oxidefilm can be formed because of its high etching selectivity and lowdielectric constant, so that finer fabrication can be attained.

Embodiment 3

The patterning of the first layer electrode sometimes brings about filmloss of the gate oxide film, but in this Embodiment, the film loss maybe supplemented by forming the silicon oxide film by a CVD process.

In the Embodiments above, a charge transfer electrode having asingle-layer electrode structure is described, but the same isapplicable also to a charge transfer electrode having a two-layerelectrode structure.

At this time, a mask needs to be used at the patterning of not only thefirst layer electrode but also the second layer electrode. In thepatterning of these first and second layer electrodes, a two-layer filmconsisting of a silicon oxide film and a silicon nitride film may beused as the hardmask. By virtue of constructing the hardmask by atwo-layer film, not only the pattern precision but also the reliabilityas an insulating film are enhanced. Moreover, in the flattening step byCMP or resist etchback, where separation of the electrode is alsoeffected, the film acts as a removal-preventing layer (etching stopper)and therefore, the yield can be more enhanced.

The metal constituting the silicide is not limited to tungsten but maybe appropriately changed to titanium (Ti), cobalt (Co), nickel (Ni) orthe like. Also, the silicon layer is not limited to the polycrystallinesilicon but may be appropriately changed to an amorphous silicon layer,a microcrystalline silicon layer or the like.

Furthermore, the production method is not limited to the above-describedEmbodiments but may be appropriately changed.

As described in the foregoing pages, according to the present invention,the gate oxide film is constituted by a two-layer structure consistingof a silicon oxide film and a metal oxide thin film, so that a highlyreliable charge transfer electrode with high withstand voltage can beformed. Also, the interelectrode insulating film can be thinned andtherefore, the present invention is effective for the fabrication of afine and high-sensitivity solid-state imaging device such as compactcamera.

The present application claims foreign priority based on Japanese PatentApplication (JP2005-231010) filed Aug. 9, 2005, the contents of which isincorporated herein by reference.

1. A solid-state imaging device comprising: a semiconductor substrate; aphotoelectric conversion section; a gate oxide film comprising atwo-layer film containing a silicon oxide film and a metal oxide thinfilm; a charge transfer section comprising a charge transfer electrodefor transferring an electric charge generated in the photoelectricconversion section, the charge transfer electrode comprising: a firstelectrode comprising a first conductive film; and a second electrodecomprising a second conductive film, the first electrode and the secondelectrode being disposed on a surface of the semiconductor substratethrough the gate oxide film and alternatively arranged; and aninterelectrode insulating film comprising a sidewall insulating filmcovering the lateral wall of the first electrode, the interelectrodeinsulating film separating and insulating the first electrode from thesecond electrode.
 2. The solid-state imaging device as claimed in claim1, wherein the metal oxide thin film has high dielectric constant. 3.The solid-state imaging device as claimed in claim 2, wherein the metaloxide thin film comprises at least one element selected from the groupconsisting of Al, Ti, Hf, Zr, La and Y.
 4. The solid-state imagingdevice as claimed in claim 2, wherein the metal oxide thin film has lowdielectric constant.
 5. The solid-state imaging device as claimed inclaim 1, wherein the silicon oxide film comprises a silicon oxide filmformed by a chemical vapor deposition method.
 6. The solid-state imagingdevice as claimed in claim 1, wherein the silicon oxide film comprises aHTO film.
 7. A method for producing a solid-state imaging device, thesolid-state imaging device containing: a photoelectric conversionsection; and a charge transfer section having a charge transferelectrode for transferring an electric charge generated in thephotoelectric conversion section, comprising: sequentially laminating asilicon oxide film and a metal oxide thin film on a semiconductorsubstrate; forming a first electrode comprising a first conductive film;forming a silicon oxide film on the top of the first electrode;anisotropically etching the silicon oxide film by using the metal oxidethin film as an etching stopper to form a sidewall insulating film onthe lateral wall of the first electrode; and forming a second electrodecomprising a second conductive film through the sidewall insulating filmso as to be insulated and separated from the first electrode.
 8. Themethod for producing a solid-state imaging device as claimed in claim 7,which comprises: removing the metal oxide thin film on the gate oxidefilm after the forming of the sidewall insulating film, the firstinsulating film being exposed from the sidewall insulating film.
 9. Themethod for producing a solid-state imaging device as claimed in claim 8,wherein the second electrode is formed by removing and flattening thesecond conductive film on the first electrode to separate the secondconductive film so that the second electrode can be formed between thefirst electrodes.
 10. The method for producing a solid-state imagingdevice as claimed in claim 8, wherein the forming of the first electrodecomprises: forming the first conductive film; forming a hard maskcomprising an insulting film on the first conductive film; andselectively removing the first conductive film by using the hard mask.11. The method for producing a solid-state imaging device as claimed inclaim 10, wherein the hard mask comprises a two-layer film containingthe silicon oxide film and a silicon nitride film, and the firstinsulating film is laminated on the hard mask.